Body mass index has a greater impact on pregnancy outcomes than gestational hyperglycaemia

Abstract

Aims/hypothesis: We evaluated diabetes-related pregnancy outcomes in a cohort of Spanish women in relation to their glucose tolerance status, prepregnancy BMI and other predictive variables. Methods: The present paper is part of a prospective study to evaluate the impact of American Diabetes Association (2000) criteria in the Spanish population. A total of 9,270 pregnant women were studied and categorised as follows according to prepregnancy BMI quartiles and glucose tolerance status: (1) negative screenees; (2) false-positive screenees; (3) gestational diabetes mellitus (GDM) according to American Diabetes Association criteria only; and (4) GDM according to National Diabetes Data Group criteria (NDDG). We evaluated fetal macrosomia, Caesarean section and seven secondary outcomes as diabetes-related pregnancy outcomes. The population-attributable and population-prevented fractions of predictor variables were calculated after binary logistic regression analysis with multiple predictors. Results: Both prepregnancy BMI and abnormal glucose tolerance categories were independent predictors of pregnancy outcomes. The upper quartile of BMI accounted for 23% of macrosomia, 9.4% of Caesarean section, 50% of pregnancy-induced hypertension and 17.6% of large-for-gestational-age newborns. In contrast, NDDG GDM accounted for 3.8% of macrosomia, 9.1% of pregnancy-induced hypertension and 3.4% of preterm births. Conclusions/ interpretation: In terms of population impact, prepregnancy maternal BMI exhibits a much stronger influence than abnormal blood glucose tolerance on macrosomia, Caesarean section, pregnancy-induced hypertension and large-for-gestational-age newborns.

Pregnancy plasma glucose levels exceeding the American Diabetes Association thresholds, but below the National Diabetes Data Group thresholds for gestational diabetes mellitus, are related to the risk of neonatal macrosomia, hypoglycaemia and hyperbilirubinaemia

“…Other studies [20][21][22] with limited power have examined the association between the ADA thresholds [6,9] with perinatal complications among white women who did not meet the NDDG criteria [5]. Magee et al [20] reported that among 34 women who met only the ADA criteria [9] the average percentage incidence of the composite measure of 33 possible perinatal complications was 41% higher than in women with normal screening.…”

“…The Toronto Tri-Hospital Gestational Diabetes project [21] found that the proportion of infants with birthweight >4,500 g was higher among 115 women who met only the ADA thresholds [9] than in 2,940 women with normal screening (6.1 vs 1.9%). Recently, Ricart et al [22] reported that after controlling for possible confounders, the risk of macrosomia (defined as birthweight >4,000 g) was somewhat higher in 263 women who met only the ADA criteria [9] than in 6,350 women with normal screening (OR=1.45, 95% CI=0.83-2.52). In our multiethnic population, after controlling for confounders, women with GDM by only ADA criteria [9] had an increased risk of delivering an infant with macrosomia (OR=2.68).…”

Diabetes and pregnancy: beyond glucose?

“…The study by Ricart et al takes the same story into the general population [15]. This Spanish population study demonstrates that pre-pregnancy BMI is a more important predictor of foetal macrosomia than gestational blood glucose control, although this, too, is important.…”

“…Two papers in the present issue of Diabetologia address these non-glycaemic contributors to pregnancy outcome [14,15]. Kerssen et al demonstrate that when women with diabetes achieve HbA 1 c levels within the 'acceptable' range during pregnancy, variations around such values contribute only minimally to the birthweight of the child [14].…”

High Birthweight and Cancer: Evidence and Implications

“…Positive associations have also been found for multiparity, a previous macrosomic infant, male fetus, maternal and paternal birthweight, ethnicity, gestational hypertension, preeclampsia, and increased interpregnancy interval (16). However, recent studies suggest that high prepregnancy body mass index, along with maternal weight gain during pregnancy, are the most important predictors of having a high-birthweight infant (17)(18)(19). With adult overweight and obesity increasing substantially over the last few decades in many developed countries (prevalence now approaching 66% in the U.S.), an increase in the prevalence of high-birthweight infants would be no surprise.…”